Obese Mice Have Impaired Brain Insulin Transport
Reversed by starvation or triglycerides
FRIDAY, April 18 (HealthDay News) -- Obese mice have impaired transport of insulin into the brain, which regulates weight, and which is reversed by starvation or triglycerides, according to research published online April 10 in Endocrinology.
Akihiko Urayama, Ph.D., and William A. Banks, M.D., from Saint Louis University School of Medicine, injected obese and lean mice with insulin intravenously and examined its transport across the blood-brain barrier.
The researchers found that insulin transport was significantly impaired in the obese mice, which was reversed by starvation for 48 hours. In contrast, brain perfusion of insulin to estimate uptake from the cerebral circulation, which negates the influence of blood-borne factors, showed similar transport rates in lean, obese and starved obese mice. In brain perfusion of starved obese mice, the triglyceride triolein significantly increased insulin uptake while decreasing leptin uptake.
"Thus, circulating triglycerides are one of the systemic modulators for the transport of insulin across the blood-brain barrier," Urayama and Banks conclude.